// 
// Copyright (c) 2004-2006 Jaroslaw Kowalski <jaak@jkowalski.net>
// 
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without 
// modification, are permitted provided that the following conditions 
// are met:
// 
// * Redistributions of source code must retain the above copyright notice, 
//   this list of conditions and the following disclaimer. 
// 
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution. 
// 
// * Neither the name of Jaroslaw Kowalski nor the names of its 
//   contributors may be used to endorse or promote products derived from this
//   software without specific prior written permission. 
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 
// THE POSSIBILITY OF SUCH DAMAGE.
// 

using System;
using System.Text;
using System.Reflection;
using System.Collections;

using NLog.Config;
using NLog.Internal;
using System.Runtime.InteropServices;

namespace NLog
{
    internal class CurrentTimeGetter
    {
        delegate DateTime GetDelegate();

        private static GetDelegate _getDelegate;

        static CurrentTimeGetter()
        {
            // this is to keep Mono compiler quiet
            _getDelegate = new GetDelegate(NonOptimizedGet);
            _getDelegate = new GetDelegate(ThrottledGet);
        }

        public static DateTime Now
        {
            get { return _getDelegate(); }
        }

        private static int _lastTicks = -1;
        private static DateTime _lastDateTime = DateTime.MinValue;

        static DateTime NonOptimizedGet()
        {
            return DateTime.Now;
        }

        static DateTime ThrottledGet()
        {
            int t = Environment.TickCount;

            if (t != _lastTicks)
            {
                DateTime dt = DateTime.Now;

                _lastTicks = t;
                _lastDateTime = dt;
                return dt;
            }
            else
            {
                return _lastDateTime;
            }
        }
    }
}
